Techniques related to video coding with a multi-pass prediction mode decision pipeline.

According to one to one exemplary embodiment, the disclosure provides a method of coding prediction for screen video. The method classifies a plurality of coding blocks into a plurality of block types by using a classifier; and uses a computing device to filter at least one candidate block from the plurality of coding blocks, according to the plurality of block types of the plurality of coding blocks, and compute a first candidate motion vector set of a type-based motion merge mode and a second candidate motion vector set of a type-based advanced motion vector prediction mode, wherein each of the at least one candidate block has a block-type different from that of a current coding block.

According to one to one exemplary embodiment, the disclosure provides a method of coding prediction for screen video. The method classifies a plurality of coding blocks into a plurality of block types by using a classifier; and uses a computing device to filter at least one candidate block from the plurality of coding blocks, according to the plurality of block types of the plurality of coding blocks, and compute a first candidate motion vector set of a type-based motion merge mode and a second candidate motion vector set of a type-based advanced motion vector prediction mode, wherein each of the at least one candidate block has a block-type different from that of a current coding block.

A method and apparatus for deriving fine-grained motion compensated prediction of boundary pixels in a video coding system are disclosed. Embodiments of the present invention determine one or more neighboring coding units (CUs) adjacent to a current coding unit (CU). For each neighboring CU, motion-compensated prediction is derived for each neighboring CU using the MV of the neighboring CU. The pre-generated predictors at a bottom side or a right side of each neighboring CUs are derived and stored on a smallest CU (SCU) basis. The pre-generated predictors and the motion compensated predictor for a current boundary pixel are combined using weighting factors to form a final predictor for the current pixel.

A method and apparatus for deriving fine-grained motion compensated prediction of boundary pixels in a video coding system are disclosed. Embodiments of the present invention determine one or more neighboring coding units (CUs) adjacent to a current coding unit (CU). For each neighboring CU, motion-compensated prediction is derived for each neighboring CU using the MV of the neighboring CU. The pre-generated predictors at a bottom side or a right side of each neighboring CUs are derived and stored on a smallest CU (SCU) basis. The pre-generated predictors and the motion compensated predictor for a current boundary pixel are combined using weighting factors to form a final predictor for the current pixel.

A method, system, and computer program product that exploits motion hints associated with rendered video frames. These motion hints are provided to a video encoder to guide a motion-compensation prediction process performed by the video encoder. Specifically, these motion hints can be used to better position a search window in a reference video frame to better capture the motion of a block of pixels in the reference video frame. Because the search window is better positioned in the reference video frame, the memory required to perform the encoding process can be reduced without sacrificing the level of encoded image quality.

According to the present invention, there is provided a method of decoding an image, the method including: deriving an initial motion vector of a current block; determining a motion refinement vector of the current block; and determining a motion vector of the current block on the basis of the initial motion vector and the motion refinement vector. Herein, the initial motion vector is derived from any one of merge candidates included in a merge candidate list for the current block.

According to the present invention, there is provided a method of decoding an image, the method including: deriving an initial motion vector of a current block; determining a motion refinement vector of the current block; and determining a motion vector of the current block on the basis of the initial motion vector and the motion refinement vector. Herein, the initial motion vector is derived from any one of merge candidates included in a merge candidate list for the current block.

A method for determining a motion vector to be used in inter-prediction of a current block of a video picture, the method comprising: obtaining an initial motion vector; obtaining at least two groups of points according to the initial motion vector, wherein a first group of the at least two groups of points only includes a first point corresponding to the initial motion vector and additional N points with N≥0 and wherein each point of the first group is closer to the first point than any point of the points of a second group of the at least two groups; and obtaining the motion vector for the current block according to the at least two groups of points and a cost function.

A method for determining a motion vector to be used in inter-prediction of a current block of a video picture, the method comprising: obtaining an initial motion vector; obtaining at least two groups of points according to the initial motion vector, wherein a first group of the at least two groups of points only includes a first point corresponding to the initial motion vector and additional N points with N≥0 and wherein each point of the first group is closer to the first point than any point of the points of a second group of the at least two groups; and obtaining the motion vector for the current block according to the at least two groups of points and a cost function.